Leaking Dam suggestions

jan_ukMay 9, 2005

Hi,

I recently had a very large dam built on the top end of our property. A very experienced dam building friend with his 33 ton excavator came over and dug our dam. It took ages - shifting clay and compacting. Unfortunately the dam is not holding water - and we have been having so much rain!! Somewhat depressing. The only expense was the cost of the diesel. I'm extremely grateful but would be happier if it had some water in it. Friend and excavator went away on a low-loader. Had thought to start distributing bags of clay pellets (Beconite?) where I think it's leaking - Any words of wisdom from anyone who's experienced similar problems gratefully accepted!!Cheers Jan :-)

Thanks Len & Pam for you words of wisdom. All the rain I was talking about in the other posting has seemed to have helped. The dam is now about 10 feet deep so its slowly on its way up. I'm hoping that the earlier movement of water out of the dam has slowed right down and even stopped.I will be keeping a close eye on the level and keeping my fingers crossed that it may have sealed itself up. I've looked up the site you mentioned Pam and now know how to tackle it, if I have to - with the 'Dispersed blanket" method using bentonite.
Cheers Jan

DNR or DPI have a site on dam management as well as the NSW dept. equivalent.

Did the contractor use the excavator or a sheeps foot roller to compact the dam? An excavator alone does very little to compact the soil as excavators and bulldozers have wide tracks to spread their weight and that stops the vehicle from bogging down, but the sheepsfoot roller does a good job because of the small projecting feet.

A few points on dam care that many fail to heed.

Never plant trees on or near the wall. If a mature tree were to die the roots rot out creating a "pipe" through the wall.

Make sure you have an effective spillway that cannot erode away if the dam overflows or the wall will follow. A good design here is the spillway is narrower at the mouth and widens out at the far end, a bit like a truncated triangle with the truncation at the mouth. This slows the velocity of the water. Additional barriers of rocks, or some sort of flow spoiler to slow the flow down to stop scouring.

As far as I can tell, your mate should have told you NOT to fill your dam, as (what was previously mentioned)the fresh compacted and hopefully claylined container needs to expand with moisture, NOT with waterpressure.Normal dam building requires a lower spillover in the first year.(unless you want it to burst:-(
Get your mate back to lower the spillover and keep a pump handy if he cannot make it time.
If your dam was build with very porous material,you can suggest to dig a 350mm sleave on top of the dam (along the lenght) smack in the middle right down and past the true ground level, then fill up with clay and dry cement(stirred in and mixed with the machine bucket)and pressed in with same.Good luck.

Hi Jan,
Check out the WaterSave Plug link below. We have worked with Department of Lands for 4 years this will seal your leaking dams with ease.
QUICK DESCRIPTION - a blend of polymers (similar to watercrystals), when sprinkled into the water get sucked into the voids and cracks, expanding creating a permanent plug and sealing the dams leak. It is safe, non toxic and environmentally friendly.
Easy application and cost effective alternative to draining or rebuilding your dam. One application generally sees your dams sealed within 7 days.
Hope this has helped.

Using these new polymers is great. We didn't have to drain the dam. We did a search and found a better product, Dam Stop Leak off E-Bay. It was cheaper and worked fantastic Sprinkled it across the top of the dam and it sealed it. Still going strong.